Last.



W. A. KRENTLER.-

' LAST.

PLIOATION IILBD SEETVIZ, 1913.

AP 1 094 1 53 Patented Apr. 21, 1914.

lllillll" E Till! Ill? Mill I! UNITED STATES PATENT OFFICE.

WALTER A. KRENTLE or 'DETE'orr, mammalian, ass'mnoit 'ro KRENTLEBFARNOLD HINGE LAST COMPANY, 015 DETROIT, MICHIGAN, A CORPORATION or MICHIGAN.

LAST.

Specification ofLetters Patent.

Patented Apr. 21, 1914..

To all whom it may concern a citizen of the United States, and resident of Detroit, county of \Vayne, State of Michigan, have invented an Improvement in Lasts, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

The desirabilty of hinging or jointedly connecting the forepart and heel part of a last hasbeen recognized by the trade, as well as by many inventors for many years, but

, the adoption of the hinged last has been hampered because'of the difficulty ofgetting great strength at the joint to resist the leveling, heeling and treeing pressures. The jointing devices have always necessitated cutting away so much of the wood as to weaken the last. The progress of shoe manu-- facture has also brought other requirements forward with more prominence of late years so that it is now considered necessary to have a hinged last provided with a lock which will positively lock the last in extended position, and this has heretofore necessitated still furthercutting away of the already frail wood. On the other hand, recent shoe stylesfhave tended toward requiring a last having an extremely thin crown of the forepart and cone of the heel part, so that the problem of jointing these lasts has become still more difficult, as the formation of sockets, kerfs I other provision for a look at these regibns of the, last has been thereby rendered practically imposv sible because of its weakening efiiect on the already thin and weak crown and cone portions.

My present invention aims to eliminate all the aforesaid disadvantages of the hinged last, my invention being applied to the wellknown Kant-break? last, one form of' the buckling pressure of the leveling ma '1' "chine, for instance, comes on the wood end- Be it known that I, W'ALTER A. KRENTLER,

wise of the knuckle between the pintle of the h nge and the outer end of the knuckle, and

as the wood is short in length at this point, i

mg the lessened amount of wood available (as above explained) and the greater pressures and more rapid movements now exacted, by extending the same general kind of dowel-like joint-member as in Patent 036,138 above and anchoring the said extended or prolonged joint-member back in the body of the heel part at a considerable distance from the pintle, and forward in the forepart at a considerable distance from said pintle, sothat, instead'of the holding strain being borne mostly at the knuckle and brought by the pintle on the frail wood of said knuckle, said knuckle is relieved of said holding strain and is' depended upon mostly for its other'great strength-giving and lastalining features and functions, while the main holding strain is brought at said two remote anchor points in the heel-part and forepart respectively, where the. wood .en

'tirely surrounds or envelops the. dowel-like ends in its circumferentially uncut integrity and at points where it is thickestand strong est and largest in mass or bulk, and hence best adapted to receive said strain. A- further important advantage of my invention isthat just mentioned, viz., although having the hinge members extended from the knuckle in opposite directions far into the solid wood, itleaves the Wood largely uncut, or in other words, provides a minimum of removal of the wood. The advantage of this will be. apparent by hearing in mind that necessarily there is only a small andrelativelyfrail amount of wood' at the waist of a last anyway, especially a hinged last, and any invention which eliminates the necessity of cutting away this wood, results in making a correspondingly stronger and longer lived last. Alsov in the preferred embodiment of my invention, I provide anchoring members or hinge parts, which snugly fit the anchor cavities and therefore maintain the last fully and advantageously lockingjfeature, while affording a strong- ..ment of the automatic locking mechanism within the space occupied by said extended members and at the knuckle, wherebyv the last when in extended position is automatically locked-with suflicientstrength to resist the many collapsing pressures and strains applied during the process of shoe manufacture thereon, particularly during the heeling and leveling machine operations and yet the knuckle is not weakened nor any of the wood cut into or removed. This automatic and rigidlocking of the last in extended position, nevertheless is so devised as to permit the last to-be readily flexed by hand when in flexed posit-ion.

for insertion in or removal from a shoe, and preferably, this automatic locking feature :also' is effective to. lock the last in either jflexed or extended position, preferably with greater locking force when in the latter than Furthermore, a subordinate advantage is that I so arrange the automatic locking devices that they are entirely'conoealed from view, affording no exposed portions on which the shoe upper or lining may catch. The locking devices are contained within the same sockets which are cut or bored for the hinge members; this featureis of particular importance in enabling my improved last to be economically manufactured and assembled, as well as in affording a strong construction at the knuckle. The locking devices are formed to exert their locking tension directly upon the metallic members constituting the hinge-and do not bear on the wood of either forepart or heel part, such a wooden bearing being objectionable as it quickly wears and eventually becomes loose and so weakens the locking effect.

In the'preferred formof my invention as herein illustrated, I provide in the forepart and heel part a simple bored socket, extending directly into the center of the wood of each part, where the wood is tough, most massive or thickest and most solid, suchbores being made in line with each other and with the pivot point in the knuckle on which the two parts are to be swung. I then provide a tubular hinged member which will snugly fill the socket bored therefor and which will extend from one part, preferably the forepart, into the socket in the knuckle of the dther part, 2'. e. the heel part,

to 'a sufficient extent so that it will tend to take up any side or torsional strains and prevent all tendency of one last-part to shift sidewise relatively to the other last-part.

lar member also is slotted to receive the co operating hinge member which extends into a socket provided therefor in the heel part. The extreme opposite end portions of each member are pinned or riveted to their respective parts, such fastening going through the solid wood of the last remote from the edge or face of either part. I'then provide a pivotal hinge for the two members, which also preferably has a bearing in the wood of one part concentric of the knuckle. In the tubular member I provide a coiled spring which may conveniently bear upon the fastening pin or rivet holding said tubular member to its respective part, 0., the forepart and so form the outwardly extending end of the other hinge member. that said spring may look the same either in straightened or flexed position. By this construction, the pivot pin on which the two parts of the last are flexed, although it does go through a part of the wood of one part, i. 6., lengthwise of the knuckle, is, nevertheless, relieved entirely of the longitudinal strain thereon, which I have explained above has heretofore tended to break out the wood of the knuckle and thereby spring the last, be cause of the rivets or fastenings through the remote opposite end parts of each hinge member which has a bearingin the most solid and thickest portions of. the wood. Furthermore, both the hinge members are concealed from view and the locking devices are also concealed and have bearings only on the metallic parts constituting the hinge and its securing means.

Referring to the drawings, illustrating, the preferred embodiment of my invention, Figure 1 is a side view of my improved last with a portion of the wood of both forepart and heel part broken away to show the hinge, which is shown partly in cross section; Fig.2 is a fragmentary plan view. showing that portion of theforepart and heel part in cross section in which the hinge members are secured; and Fig.- 3 is a fragmentary side view, partly in cross section, of the last in flexed position.

In the illustrative embodiment of my intion I have utilized that type of last known in the trade as the Kant-break last, althou h the invention is obviously applicable to *ot er types and forms of knuckle joint: lasts. The forepart 1 and heel part 2 are of usual external contour, having a knuckle portion 3 formed-on the heel part and fitting into a corresponding concave socket on operating recess 4, into the central part of the wood of the forepart, and a corresponding socket 8 into the heel part 2 and similarly located therein. Where this bore cuts the knuckle 3 I cut away a portion thereof as indicated at 9, but of a width corresponding to the width of the tubular dowel member 10, to permit said tubular member 10 which is fitted into the socket 7 to swing during the flexing of the last while at the same time hugging against the sides of the cut as shown best in Fig. 2. -The tubular member 10 is formed with a ,slot 11 in which the cooperating dowel member 12 of the hinge is fitted. The hinge member 12 ex- ,tends into the socket 8 in-the heel part and receives a pin or rivet 13 th erethrough', which passes through the solid thick wood of the heel part, and the tubular member 10 receives a corresponding fastening member 14 passing therethrough and fitting withinand through the solid thick wood portion of the forepart. The overlapping portions of the-hinge members 10 and 12 are suitably bored to receive the pivot pin 15 on which the two parts are flexed, which pivot pin 1s set through the wood or knuckle 3 concentric with the outer face of said knuckle and with the corresponding face 4 of the fore-' part, so as to insure smooth, yet snug, tight,

turning of the knuckle 3 in the socket cavity 4, as clearly shown in Figs. 1 and 3.

The forward portion of the hinge member 12 is provided with an extension beyond the pivot pin 15. whichpresents a' concave face 16 and a second face 17 each meeting at a point 18, said faces being preferably hardened, or the entire member 12 may be of hardened steel. Within the tububearing when the last is in extended posi-v tion, as shown in Fig. 1. The spring 19 forcing the member 20 into firm engagement with the forward portion of the hinge member 12 will require considerable power to permit the member 12 to be flexed and the ball 20 to be forced beyond the point 18 and permit it to rest on the face 17. ,In either position with the member 20 in contact withthe concave face 16, or resting on the face 17, the last is locked in position.

Furthermore, asthe last is flexed and as soon as the member 20, (when said meme her is a ball or the like,) is forced sufliciently beyondthe point 18 and begins to traverse either face 17 or 16, the spring 19 willautomatically complete the flexing or straightening of the last and will similarly seat the last in either straightened position, as shown in Fig. 1, or in flexed position as shown in Fig. 3. c

It will be noted that the wood of both forepart and heel part is cut away to a minimum extent, and futhermore that the hinge members practically fill up the wood so cut away particularly the tubular member 10, and that portion of the hinge member 12 within its socket which is free of the member 10 may also be tubular if desired. I prefer 'to employ a headed bolt for the fastening member 13, and may also form the pins 13 and 14 as taper or wedge members, thus further forcing the forepart and heel part 2 into close contact around the knuckle 3 in assembling the last. The fastenings 13 and 14 being through the solid uncut wood part of thelast at the thickest portions thereof and remote from the abutting faces 3 and 4 effectually prevent the loosening of the hinge at said abutting faces and thus alwaysretain the two parts of the .last in firm, close, and unremitting contact, while permitting the same to be readily flexed. The automatic locking devices are entirely concealed within the tubular member 10 and the spring 19 being seated upon the fastening 14, has a firm metallic bearing which is fitted as a part of the hinge construction and therefore furnishes a bearing for said hinge Without special work. of the forepart may be fined down and even 'concaved as required by recent extreme 1 styles without'interfering with or weakening the hinge or locking members in any way whatever, and the entire exterior contour of the wooden portions of both forepart and heel part may be varied to the greatest extent desired without interfering with the hinge construction which is seated in the central portions of the two wooden parts. Coupled with this, and with the strong knuckle-joint combination already explained,- the automatic locking feature of the two dowel members also has its bearing and wearing portions upon met-a1, preferably hardened steel, and there is therefore nothing to wear loose in my improved construct-ion, and both look and binge are always maintained in their initial efficiency. The manufacture of the last is simple and the entire arrangement.permi-ts an easy and The crown 21 parts.

manufacturing, as already explained.

I make no claim to the knuckle joint alone nor to the dowelhinge alone nor to the plunger locking device alone, as each of these has existed before, but not in the combination nor with the advantages andresults which distinguish my invention. Dowel hinges have always heretofore been used in the general type of last known as the Tyler hinged last (whose general lines of out are typified in Patents 601,622;

' 607 ,978'; and 661,397, in which the pintle or pivot point is located at the apex of the V- gap or meeting point where the secant line from the bottomv intersects the two secant lines from the topfof the last), and have been subject to the fatal weakness inherent in all lasts of this Tyler type,vviz. that the leveling pressures and twisting movements of the forepart with relation to the heel-part have brought ashearing strain directly on the hinge at the pintle, so that they could not stand up to the severe usage of the --more modern factory-practice, One recognized advantage of the dowel hinge has been that it leaves the Wood largely uncut or integral and avoids thene'ce'ssity'of making a plane of cleavage .or tendency to split the last apart aswhen the last is sawed to receive a plate hinge (whether set horizontally as in the Tyler last or vertically as in Patent 608,006 already mentioned), but in theonly instance known to me which reached a com- .mercial point (661,397 above) it was necessary to employ two widely spaced apart do welsin order to maintain the joint of the last-parts at the bottom level or alined and to resist twisting tendency. The only instance known to me in the priorart where 'it has been proposed to employ a single dowelhinge is shown inPatent 64:2,341, in which it was attempted to overcome the tendency to, twist'by making the dowel 8-shaped in cross-section, set with its greatest diameter extending vertically in the last, but it was found in practice that there was still a fatal tendency of the last-parts to twist on each other andalso that there was a tendency to .split. to strength to resist the shearing strains above mentioned and the twisting strains, also above mentioned, were met satisfactorily for several years by the knuckle-joint lastalready explained hereinbefore, in which the tory requirements.

The increasing exactions as.

semi-cylindrical projection or knuckle of wood secures a strong supporting resistance by its engagement with its bed or socket throughout the entire width of the last whereby both the shearing strain is effectually resisted and also the tendency of the last-parts to twist on each other, but, as I have explained in the earlier part of this specification, the still greater exactions of the still more advanced shoe factory practice finally proved too much for this last as then made (Pat. 936,138, being the most advanced example on the market), as the lastjoint or connection would give or yield sufficiently to permit the knuckle to loosen in its socket and hence allow the forepart to separate slightly from the heel-part, causing an unevenness on the bottom and sides and a liability of the bottom to gap open slightly and'thereby become liable to pinch the lining and crease or cut the leather. My present invention, therefore, combines the great strength of the knuckle joint and its elimination of the shearing-strain and twisting-strain weaknesses with the great strength 'and anti-splitting advantages and simplicity of the dowel hinge, with the marked result that the hinged last is again rendered capable of meeting the latest fac- Viewed from another standpoint, the main feature of my invention may be stated to reside in preserving all the advantages of the Kantbrea-k last while removing its weakness by taking practically all the strains which previously existed between therpintle and the knuckle (which previously had to endure all the lengthwisepull strain of the leveler) away from this point and transferring said strains to the thickest heaviest portions of the forepart and heel-part by employing a jointed dowel .hinge and anchoring its opposite ends as far away from the knuckle as the last construction will permit. Thus I have succ eeded in bringing together in a single compact construction the great strength resulting from leaving the wood uncut transversely by using a dowel hinge (reaching its vmaximum of strength in the single dowel),

the great self-alining and vertical-strainsustaining features of the knuckle-joint construction, and the transference to the thick est heaviest wood-mass of the fore-part and the heel-part of the points of resistance to lengthwisepulland strain under the leveling-machine. At the same time I have eliminated the tendency to shear off and twist which has always heretofore existed in connection with the attempt to use a dowel hinge, the tendency of the pintle to breakout endwise the cross-grain wood of the knuckle in the Kantbreak last, and the tendency to split along the planes of the saw kerfs which is present in the remaining forms of hinged lasts which necessitate the presence of saw kerfs. And finally I haveso combined all these features of construction and advantagethat, without cutting the wood or changing the dowel or otherwise complicating the structures, the last is made self-locking in both its lengthened and shortened positions by the self-contained and self-adjusting spring lock. This form of lock is not new in and of itself (being shown in Patent 721,717), but only as applied to my particular construction of hinge and relation of last-parts.

My invention will be more particularly defined in the following claims, taken in connection with the foregoing description and difi'erentiation from the state of the prior art.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A hinged last having its forepart and heelart fitted to each other with a knuckle joint, combined with a dowel-like hinge connection consisting of at least two dowel members pivoted to swing intermediate its length in the knuckle and anchored remote from said pintle at its opposite ends within the solid portions of the forepart and heel-part respectively.

2. A last, having a forepart, a heel-part, a portion of the wood of one part extending about the pintle on which said parts swing, and a hinge having a pintle on which said parts swing and having opposite dowel portions extending lengthwise of the last within said forepart and heel-part respectively and anchored adjacent their opposite ends in the body of the respective last-parts,

3. A last, having-a forepart, a heel-part, a knuckle extending widthwise of the last on one of said parts and the other part containing a complemental concave socket in which said knuckle fits and turns, said knuckle having a radius sufiiciently small to have a substantially semi-cylindrical engagement with the socket, whereby a. maximum of resistance to vertical and twisting strains is afiorded, each last-part having a longitudinal hole bored therein from said knuckle, and a hinge connection consisting of two dowels pivotally connected by apintle concentric of said knuckle and extending thence in opposite directions within said two holes and anchored transversely of the last at the ends of the respective dowels within said respective last-parts. 4. A last, having a forepart, a heel-part, a knuckle extending widthwise of the last on one of said parts and the other part containing a complemental concave socket m which said knuckle tits and turns, said knuckle having a radius sulficiently small to have a substantially semi-cylindrical engagement with thesocket, whereby a maximum of resistance to vertical. and twisting strains is afior'ded, each 1ast-parthavinga longitudinal hole bored therein from said knuckle, and a hinge connection consisting of two dowels pivotally connected by a pintle concentricfof said knuckle and extending thence 1n opposite directions within said .two holes and anchored transversely of the last at the ends of the respective dowels within said respective last-parts at the points one of said parts and the other part containing a complemental concave socket in which said "knuckle fits and turns, said knuckle having a radius sufiiciently small to have a substantially semi-cylindrical engagement with the socket, whereby a maximum of resistance to vertical and twisting strains is afforded, each last-part having a longitudinal hole bored therein from said knuckle, and a hinge connection consisting of two dowels pivotally connected by a pintle extending approximately the width of the last concentric of said knuckle and extending thence in opposite directions within said two holes and anchored transversely of the-last at the ends of the respective dowels within said respective last-parts.

'6. A last, having a forepart, a heel-part, a knuckle extending widthwise of the last on one part and the other part containing a complemental concave socket in which said knuckle fits and turns, said last-parts containing holes extending lengthwise of the last in opposite direct-ions from said knuckle and socket at approximately the widthwise middle of the last, and a hinge connection consisting of a dowel-like member occupying. the hole in the forepart, a second dowellike member occupying the hole in the heelpart, said two members mutually overlapping at' their meeting ends in the knuckle, a pintle mounted within the knuckle concentrically thereof and passing through said overlapping ends as a center ofv pivotal movement thereof, a transverse pin extending transversely of the forepart through the forward end of the first mentioned member at the point of approximately greatest thickness and strength of wood-mass of said forepart, and a second transverse pin extending transversely through the heel-part and through the rear end of the second mentionedv member at the point of approximately greatest thickness and strength-0f wood-mass of saidheel-part, one of said dowel-like members being tubular to fit its hole, the knuckle having a transverse recess corresponding in width to the diameter of said tube, for preventing widthwise shifting of one last-part on the other last-part.

7. A last, having a forepart, a heel-part,

a knuckleextending widthwise of the last the second mentioned member at the point on one part and the other part containing a complemental concave socket inwhich said knuckle fits and turns, said last-parts containing holes extending lengthwise of the last in opposite directions from said knuckle and socket at approximately the widthwise middle of thedast, and a hinge connection -and lock consisting of a dowel-like member occupying the hole in the forepart, a second dowel-like member occupying the hole in the heel-part,csa id two members mutually overlapping at their meeting ends in the knuckle, a pintle mounted within the knuckle concentrically thereof and passing through said overlapping ends as a center of pivotal movement thereof, a transverse pin extending transversely of the forepart through the forward end of the first mentioned member at the point of approximately greatest thickness and strength of wood-mass of said forepart, a second transverse pin extending transversely through the heel-part and through the rear end of of approximately greatest thickness and shifting of one last-part on the other lastpart, a coiled spring held under compression within said tubular dowel against the said transverse pin thereof, and a ball supported loosely by the opposite end of said spring within said tubular member, the adjacent end of the other dowel member having opposite oblique locking seats for said I ball to occupy when the last is in fully lengthened position and fully shortened po sition respectively.

In testimonywhereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WALTER A. KRENTLER. Witnesses:

NELLIE E. CHAVENELLE, B. H. KOCHER. 

